Adjustable-pull trigger-mechanism for firearms



April 23, 1935.- L. STIENNON 1,993,596

' ADJL ISTABLE I PULL TRIGGER MECHANISM FOR FIREARMS V Filed Oct. 7, 1932 S-Sheets-Sheet 1 April 23, 1935. STIENNON 3 5 ADJUSTABLE PULL TRIGGER MECHANISM FOR FIREARMS Filed bet. 7, 1932 "5 sn'eets sheet 2 .lll.

, QQ wwbww I L. STIENNON 1,998,596 ADJUSTABLE PULL TRIGGER MECHANIIISM FORVFISREARMS FiledloctL 7, 1932 f5 sheets-sh'eet s April 23,; 1935.

m v R 4 8 bw m$ |||\II E mm? fis NM Ra Ma S i *Q xN v v. mm Mn h April 23., 1935 L, s o 7 1,998,596

ADJUSTABLE PULL TRIGGER MECHANISM FOR FIREARMS Filed Oct. 7, 1932 S SheetS- Sheet 4 Z0 Z 2/ 56 i2 V 5a 55 22 52 5 I v Z 22 April 23,1935. STlNNQN 1, 98,

' ADJUSTABLE PULL T IGGERMECHAMS FQR FIREARMS 5- Sheets-Sheet 5 Filed. Oct. 7, 1932 I i UNITED S Patented A r. 23, 1935 r Application. October '7,

9 Claims.

This invention" relatesto. an improvement in trigger-mechanisms for firearms and relatesin particular to that; class-of trigger-mechanisms in which a sear is actuated by a separately-formed trigger. 1 .1 n I Since theinception of the mass production of standardizedfirearma the adjusting or regulatpear from the following. '.My invention further consists in an adjustable trigger-mechanism for .firearms'having-certain ing within satisfactory limits of pressure of the so-called trigger-pull, i. e.,.the force required to release the sear for firing the arm,has been a difiicult and, in :a practical sense, an unsolved problem. Efiorts have been heretofore made to provide forjsuch regulation or adjustment by more or less makeshift expedients such, forv instance, as by filing or bilstoning thesear-nose, or by bending or changing the thickness of the springsinvolved so as to effect an increase or decrease in tension.

None of the prior modesoi adjustingor regulating the triggerpull have afforded either the manufacturer or the user of the arm any really practicable. means of regulating or adjusting the trigger-pull to suit individual tastes. or requirements, or to compensate for changes due to wear,.etc. 1 One of the main objectsof my. present inventionis to provide a trigger-mechanism embodying simple,'re1iable and effective means. for, regulating or adjusting the trigger-pulL? i. e., the

force required to be exerted upon thetrigger' in.

posed between the trigger and sear a third memher which may be characterized as a shiftable transmitting-member? inasmuchas it serves in a broad sense to transmit the movement of the trigger to the sear, and shiftable in whole or in part withrespect to atleast one thereof. for varying the trigger-pull, as will morefully apfeatures of construction and, combinations and arrangements of parts as will more fully appear from the following and be set forth in:the ap-.

present invention is to ADJUSTABLE-PULL TRIGGER-MECHANISM FOR FIREARMS 1932. Serial No. 636,634

purpose of illustrating my invention include a. manually-adjustable transmitting-member interposed between and movable with respect to the respective pivot points of the trigger and the sear of the firearm, in such manner that the effective arm length of one or more of the, levers involved may be adjusted for the purpose mentioned. I

In the accompanying drawings:

Fig. 1 is a broken View partly in side elevation and partly in vertical central-longitudinal section of the frame-portion of a shot gun, in which is incorporated a trigger-mechanism constructed in accordance with my invention, the gun being cooked and the transmitting-member being shown as adjusted to the limit of its movement in the direction required for increasing the force required to be exerted upon the trigger; V

Fig. 2 is a view corresponding to Fig. l, but showing the transmitting-member as adjusted to the limit ofiits movement in the direction required for easing or lessening the force required" to be exerted upon thetrigger;

Fig; 3 is a viewcorresponding to Fig. 2, but showing the parts in the positions which they assume when the trigger is pulled and the sear disengaged from the hammer, which latter is shown as swung into itsfiring position;

Fig. l is a broken transverse sectional view, taken on the line 4-4 of Fig. 1;

Fig. 5 is'a similar View, taken on the line 5-5. of Fig.1; 7

Fig. 6 is a similar view, taken on the line 6-6 of Fig. 1;

Fig. '7 is a similar View, taken on the line 1'l of Fig. 1;

Fig. 8 is a broken top or plan view of the trigger-plate, detached, and showing the parts of myimproved trigger-mechanism which are normally organized therewith; V

.Fig. 9 is a perspective view of the rotary adjusting-member, detached; Fig ll) isa perspective view of the transmitting-member, detached; r

Fig. 11. is a similar View of the adjusting-link,

detached;

Fig. 12'is' a broken view in transverse longitu: din'al section, taken on the line l2|2 of Fig.2; )Fig. 13 is a perspective View of. the trigger plate, detached, together with the parts of my improvedimechanism normally organized therewith, the sear being also shown in appropriate relationship to the other elements;

' Fig. 14.15 a broken schematic view'illustrating another form which my invention may assume; and

Fig. 15 is a similar view illustrating still another form which my invention may assume.

The particular firearm herein chosen in Figs. 1 to 13 inclusive for the illustration of my invention includes a frame 28, a butt-stock 2! and a trigger-plate 22, all of usual characteristics.

For the purpose of securing together the frame 20, butt-stock 2! and trigger-plate 22, I employ two or more fastening-screws 23 and 24, the former of which projects downwardly through the rearwardly-extending tang 25 of the frame 20, through the butt-stock 2i and into a threaded bore 25 formed in a lug 21 upstanding from the trigger-plate 22. The screw 2 before referred to passes upwardly through the rear end of the said trigger-plate 22, through a suitable perforation in the butt-stock 2|, and into a threaded bore 28 formed in the tang 25 adjacent the rear end thereof in the usual manner of firearms.

The' trigger-plate 22 before referred to is formed adjacent its lug 2'! with a vertical longitudinal slot 29 which intersects a vertical slot 39 formed in the rear face of the said lug Zl and virtually constitutes an extension of the said slot 29. Installed'in the slots 29 and 39 is a pivotal trigger 3! of usual form, and hung upon a transverse pin 32 mounted in the lug 21.: The slot 30 in the lug 27 has intersecting it an upwardly and forwardly inclined socket 33 receiving the rear end of a helical trigger-spring 34 which bears against the trigger, as shown, and exerts a mild eifortto swing the said trigger in a counterclockwise direction to normally maintain the upper edge or lifting-face 35 of the same in contact with a transverse transmitting-pin 36 mounted in and forming a feature of a transmitting-member 31.

'The transmitting-member 31, just above referred to, is mounted with capacity for both longitudinal sliding movement and vertical rocking movement, as will more fully appear, and has the under face of its forward portion formed with a longitudinal groove 35 freely receiving the rear portion of the trigger 3i and traversed laterally by the transmitting-pin 36 before referred to. The rear portion of the transmitting-member 3'! is shaped to form a tongue 39 positioned between a pair of complementary ears 45-40 upstanding from the upper face of the trigger-plate 22.

adjacent the rear end thereof and formed integral therewith. Extending transverselybetween the ears 255fi just referred to is a pin ll which also passes through a longitudinal slot 52 formed in the said tongue 39 and designed'to permit the transmitting-member to both rock and move bodily longitudinally with respect to the gun structure. r

At its forward end where it joins the bodyproper of the member 31, the tongue 39 is formed in its upper edge with a coupling-notch 43 receiving a coupling-finger M laterally-offsetting from the side edge of a sheetmetal adjustinglink 55 extending forwardly along one side of the transmitting-member 31 and lug 21. Adjacent its extreme forward end, the said link 45 is provided with a downwardly-offsetting couplingfinger 46 entering into an eccentrically-positioned socket 51 formed in the upper surface of the flange-portion 48 of a rotary adjusting-member 49, which latter also includes a short'cylindrical body-portion 50 provided in its under face with a kerf 5| for the reception of a screw driver or other tool for the purpose as will hereinafter appear. The flange-portion 48 of the said adjusting-member 49 is seated in a recess 52 formed in the upper face of the trigger-plate 22 and intersecting a coaxial passage 53 through which the body-portion 551 of the said adjusting-member extends downwardly to expose its slotted under face through the under face of the said triggerplate 22.

For the purpose of locking the adjusting-link 15 in any given position of its movement to thus in turn lock the transmitting-member 31 against accidental longitudinal movement, I provide a locking-screw 55 threaded through a vertical threaded-bore 55 in the trigger-plate 22 adjacent one edge thereof and having its upper end engageable with the under, face of the adjacent portion of the link 55 to clamp the same against the under face of a longitudinal passage 55 formed in the frame 20 immediately above the trigger-plate 22, as clearly shown in Fig. 4.

Pivotally mounted upon a transverse pin 51 is a skeletonized sear 58 having the usual characteristics and including a'sear-nose 59 adapted to engage a sear-notch 50 formed in a swinginghammer 6| or other equivalent firing-member. The particular firing-member herein chosen for,

illustration, namely, the swinging-hammer BI, is provided with the usual hammer-springv (not shown) and carries the usual firing-pin 62 adapted to'engage the primer of a cartridge for firing the same in the usual manner of firearms. The rear portion of the sear 58 is formed'with a vertical clearance-passage 53' through which the lug 21 of the trigger-platen, as well as the upper forward portion of the trigger 3|, extends. The rear wall of the passage 53 just referred to in the sear 58 is formed by a cross-bar 64 normally overlying the upper surface of the transmittingmember 31 for being engaged thereby.

For engaging the sear-nose 59 of the sear 58 with the sear-notch 60 I employ a sheet-metal spring 65 having oppositely-projecting lateral tongues (iii-66 (Fig. 12), each of which is positioned in a rearwardly-opening notch 61 formed in the frame 20 The said sear-spring 65 is formed with a central clearance-opening 68 sub:-

stantially corresponding to the clearance-passage 63 in the sear 58 and providing a clearance for both the lug 21 and the upper forward portion of the trigger 31. Likewise, the sear-spring 65 is formed at its rear end with a cross-bar 69 resting upon the upper surface of the cross-bar 64 of the said sear and exerting a constantefiort to depress the same. Fingers l0 offsetting from the sear-spring 65 serve to interlock the rear end thereof with the cross-bar 64 of the said sear.

For the purpose of limiting the longitudinal movement of the adjusting-link 45 I employ adjacent the rear end of the latter a downwardlyextending arm 1| formed in its under edge with a downwardly-opening notch 12 receiving the pivot-pin and flanked at each of its respective opposite ends by a stop-finger 13.

With the firearm cocked as shown in Figs. 1 and 2 a rearward force exerted upon the fingerpiece of the trigger'3l will turn the latter upon its pin 32 with the effect of causing the liftingsurface 35 of the said trigger to lift the forward end of the transmitting-member 31 which will pivot upon the transverse pin 4|. The upward swinging movement of 'the transmitting-member 31 will by reason of its location beneath the crossbar 64 of the sear 58 rock the latter in a counterclockwise direction against the tension of the searfspring 65 and disen a the sear-nose. 59 from the scar-notch 6a in the hammer 6,! and thus permit the upper end of the latter, together with the'firing pin 6 2,, to be snapped fol-ward in the usual manner for firing the arm. The sear E18. and hammertl will now have assumed the positionsqin which they are shown in Fig. 3.

. Regardless of whether the. trigger-mechanism is adjusted to provide either a heavy or light. trigger-pull, the operation above referred to will be,in-al1 essentials, the same. i

In Fig. 1 the transmittingemember 31 is shown in its rearmost position in which the heaviest triggernpull withinthe range of the mechanism,

is required to. release the hammer for firing the arm. It will be noted in the figure referred to that the contact-point of the transmittingmember 3.1, i. e., the transmitting-pin 36; is now located at; its furthermost. position away from the pin 32 upon which the trigger 3| swings,so that the force required to beexerted upon the trigger for rocking the transmitting-member against'a given load Willbe at its maximum and hence the mechanism may be said to beadjusted to-require the heaviest trigger-pull within its range. Also with its transmitting pin 36 in thei'same direc tion. This movement will shift the contactpoint; i. e., the pin36, forwardlytoward the pin 32 upon which the trigger 3| swings and therefore decrease the amount of force which must be applied to the trigger'in order tofire the arm.

The movement for lessening or lightening the soecalledlftriggerpull as just above described be continued if desired until the rearmost of the stop-fingers. 73; upon the adjusting-link .45

engages with the rear face of: the pin 4.! at which 1 they are shown in Fig. 2, in which it will be noted that the transmitting-pin 38. is located in its furthest advanced position in the direction ofv the triggerepin 3.2 and therefore forward of the crossbar G4 of the sear 58.

When adjusted to afford the user the .desired trigger-pull the link and hence the transmitting-member 31 may be locked in such position of adjustment by inwardly screwing the locking-screw as as beforedescribed.

If desired in order to regulate or adjust the trigger pull, I may resort to a construction such, for instance, as that schematically shown in Fig. 14, in which the transmitting-member is in the form of ,a swinging-arm M pivotally mounted by means of a pin 15 to the rear end of the sear 58 and provided with a laterally-offsetting pin 16 entered into a notch Tl provided in the rear end of the adjusting-link 45. The lower or free end of the arm-like transmitting-member i4 is adapted to engage an upwardly-facing arcuateshaped lifting-surface 18 provided upon the upper edge' of the trigger 3!. It will be obvious by reference to Fig. 14. that when the arm 14 is swung to the limit of its forward movement, its lower end will be relatively close to the triggernin- 3i sothet the fo c requi ed o be e erted upon the tri ger forswins n th sc an fi n the arm w ll be at th minimum. Conv s ly,

rig er iii in order to rock th s ar and-fire the arm.

' In Fig.

V 1o 1.5 I have schematically shown, still another mode of carryin out my invention,

which consists. in providing the upper edge of the trigger 3| with a longitudinal groove 19 in which is mounted a transmitting-member in the form of;a slide 3!) adjustable longitudinally of the said trigger by any approved means such,- for instance, as the rotary adjusting-screw 8| shown; The slide-like transmitting-member Bil just referred to is provided with anupwardly-offsetting V contact-nose 82 adapted to engage the under side of the sear 5.8 at diiierent positions thereon within the limits of the longitudinal movement ofthe said slide. It will be obvious that when the slide-like transmitting-member 80 is at'thelimit of its forward adjustment it will diminish the.

force required to be exerted upon the trigger in order to operate the sear, and conversely when the said transmtting-member is at the limit of its rearward movement the force required tobe exerted upon the trigger will be increased to-the ximurn within the range of the device;

The various forms of' trigger-mechanisms.

herein illustrated and described are in no sense exhaustive of the various forms which my inven-. tion may assume, but are merely illustrative of some of the variants thereof. 1

In each of the embodiments of my invention herein chosen for illustration it will be noted that a transmitting-:member is employed which is adjustable withreference to both the trigger and the sear in such manner as to adjust theforce required to be exerted upon'the trigger Iforfiring the arm, though it will be understood by those skilled in the art that I do not limit my invention to the embodiments herein shown'but only as indicated in the appended claims.

I claim: 1

l. Inan adjustable-pull trigger-mechanism for firearms, the combinaticnwith the pivotal trigger and separately-formedpivotal sear thereof; of an adjustable pull-regulating transmitting-member mounted in the firearm structure independently of both the said trigger and the said sear, for both'rocking and reciprocating movement and operatively interposed between the said trigger and the said sear and'constructed and arranged to transmit the movement of the former to the latter when in any given onefof a plurality of positions of adjustment and movable toward and away from the pivots of both thereof to adjust justment; an adjusting-member exposed upon the exterior surface of the firearm for manual op eration; and means including a link for operatively connecting the said adjusting-member to the said transmitting-member for moving the same to adjust the force required to be exerted upon the said trigger for actuating the said sear.

3. 'In an adjustable-pull trigger-mechanism for firearms, the combination'with the trigger and separately-formed sear thereof; of an adjustable pull-regulating transmitting-member located within the firearm structure and operatively interposed between the said trigger and the said scar and constructed and arranged to transmit the movement of the former to the latter when many given one of a plurality of positions of adjustment; a rotary adjusting-member exposed upon the exterior surface of the firearm for manual operation; and a linkroperatively connecting the said rotary adjusting-member to the said transmitting-member for moving the same to adjust the force required to be exerted upon the said trigger for actuating the said sear.

, 4. In an adjustable-pull trigger-mechanism for firearms, 'the combination with the trigger and separately-formed sear'thereof; of an adjustable pull-regulating transmitting-member mounted for reciprocating movement within the firearm structure and operatively interposed between the said trigger and the said sear and constructed and arranged to transmit the movement of the form'erto the latterrwhen in. any given one of a plurality of positions of adjustment; a rotary adjusting-member positioned for. manipulation from the exterior of the firearmstructure; and a link operatively connecting the said rotary adjusting-member to the said transmitting-member for reciprocating the latter to adjustvthe force required to be exerted upon the said trigger for actuating the said sear. V

a 5. In an adjustable pull trigger-mechanism for firearms, the combination with the trigger and separately-formed sear thereof; of an adjustable pull-regulating transmitting-member mounted for reciprocating movement andoperatively interposed betweenthe said trigger and the said sear and constructed and arranged to transmit the movement of the former to the latter when many given one ota plurality of positions of adjustment; a rotary adjusting-member; and a link operatively interposed between the said rotary adjusting-member and the said transmittingmember forconverting a rotary movement of the former into a reciprocating movement of the latter to adjust the force required to be exerted upon the said trigger for actuating the said sear.

6. In an adjustable pull trigger-mechanism for firearma'the combination with the trigger and separately-formed sear thereof; of a rocking and reciprocating pull-regulating transmitting-lever having a slot formed therein and operatively interposed between the said trigger and the said sear for transmitting the movement of the former trigger and the said sear and designed to transmit the movement of the former to the latter when in any given one of a plurality of positions'of adjustment and to one of which it is pivotally connected and with the other of which it has adjustable sliding engagement to adjust the force required to be exerted upon the said trigger for actuating the said sear.

8. In an adjustable pulltrigger-mechanism for firearms, the combination with the trigger and separately-formed sear thereof; of an adjustable pivotally-mounted pull-regulating transmittingmember operatively interposed between the said trigger and the said sear and designed to transmit the movement of the former to the latter when in any given one of a plurality of positions of adjustment and pivotally connected to the said sear and having sliding engagement with the said trigger to adjust the force required to'be exerted upon the said trigger for actuating the said sear.

9. In an adjustable-pull trigger-mechanism for firearms, the combination with a trigger and a sear; of an adjustable pull-regulating transmitting-member mounted within the firearm structure and operatively interposed between the said trigger and the said sear in position to transmit the movement of the former to the latter; a'manual operating-nember mounted in position for manual manipulation from the exterior of the firearm without requiring the demounting of the same; and means connecting the said operatingmember to the said transmitting-member to transmit the movement of the former to the latter and thus regulate the same from the exterior of the firearm.

LOUIS STIENNON. 

